The drug had been on the market more than 20 years.“Larry Cahill, a neuroscientist at the University of California, Irvine, admits that like many fellow scientists, he used to think men and women were fundamentally the same, outside the obvious areas of reproduction and sex hormones. He says Ambien, (known generically as zolpidem) which was approved back in 1992, is a case in point. How did it happen that for 20 some years, women, millions of them, were essentially overdosing on Ambien?